From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:56714 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727411AbeI0PmH (ORCPT ); Thu, 27 Sep 2018 11:42:07 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso , Wen Xu Subject: [PATCH 4.14 51/64] ext4: check to make sure the rename(2)s destination is not freed Date: Thu, 27 Sep 2018 11:04:08 +0200 Message-Id: <20180927090257.098102014@linuxfoundation.org> In-Reply-To: <20180927090249.801943776@linuxfoundation.org> References: <20180927090249.801943776@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit b50282f3241acee880514212d88b6049fb5039c8 upstream. If the destination of the rename(2) system call exists, the inode's link count (i_nlinks) must be non-zero. If it is, the inode can end up on the orphan list prematurely, leading to all sorts of hilarity, including a use-after-free. https://bugzilla.kernel.org/show_bug.cgi?id=200931 Signed-off-by: Theodore Ts'o Reported-by: Wen Xu Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/namei.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3514,6 +3514,12 @@ static int ext4_rename(struct inode *old int credits; u8 old_file_type; + if (new.inode && new.inode->i_nlink == 0) { + EXT4_ERROR_INODE(new.inode, + "target of rename is already freed"); + return -EFSCORRUPTED; + } + if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) && (!projid_eq(EXT4_I(new_dir)->i_projid, EXT4_I(old_dentry->d_inode)->i_projid)))